1. Technical Field
The present invention relates to a vibrating element, a vibrator, an oscillator, an electronic apparatus, and a moving object.
2. Related Art
As vibrating elements, for example, sensors that detect a physical quantity such as an angular velocity or an acceleration and are used for body control in vehicles, self-position detection of car navigation systems, vibration control correction (so-called camera-shake correction) for digital cameras or video camcorders, or the like have been known. As the sensors, for example, angular velocity sensors (vibration gyro sensors) have been known (for example, refer to JP-A-2006-105614).
For example, a vibration gyro sensor disclosed in JP-A-2006-105614 includes a base portion, coupling arms extended from the base portion, driving arms extended from the tips of the coupling arms, and detecting arms extended from the base portion. When an angular velocity in a predetermined direction is applied to the vibration gyro sensor in a state where the driving arms are flexurally vibrated, the Coriolis force acts on the driving arms, and consequently, the detecting arms flexurally vibrate. By detecting the flexural vibrations of the detecting arms, the angular velocity can be detected.
The base portion or driving arms of the vibration gyro sensor is formed of, for example, a piezoelectric material. By processing the piezoelectric material using a photolithographic technique or an etching technique, the base portion or driving arms is formed.
JP-A-2012-98091 discloses a piezoelectric vibration-type yaw rate sensor (vibrator) having a plurality of detection modes (first and second detection vibration modes). In the sensor, a resonance frequency in the first detection vibration mode is made close to a resonance frequency in the second detection vibration mode to increase amplitudes at the detecting arms, so that the sensitivity of the sensor is increased.
In the sensor (vibrator) disclosed in JP-A-2012-98091, a relationship with the frequency is described, but there is no consideration of a relationship between the temperature and the frequency. Therefore, it is difficult to suppress degradation in characteristics such as frequency characteristics due to a change in temperature.